Bo had been a candidate for top office until caught in one of China's biggest scandals in decades involving his wife Gu Kailai. She and a police chief were jailed and sentenced recently over the murder of a British businessman last November.

No legal action has yet been taken against Bo but on Friday the official Chinese news agency Xinhua said Bo would "face justice" for alleged abuse of power, bribes and improper sexual relations.

Several years ago, Bo reaped national acclaim by targeting gang leaders and corrupt police as Communist Party chief in the southwestern city of Chongqing. He had been tipped for elevation to the nine-member Politburo Standing Committee.

Massive damage, claims Politburo

The Politburo statement carried by Xinhua said "Bo Xilai's actions created grave repercussions." It accused him of "massively damaging" the reputation of the party and state.

Bo had been expelled from the party, it said, as well as the elite decision-making Politburo and Central Committee "in view of his errors and culpability,"

The Politburo also warned "party organisations at all levels" to regard the case of Bo as a "negative example" that illustrated "grave disciplinary violations."

Analysts say the affair surrounding Bo exposed deep divisions with the Communist Party, because Bo retains a large following among left-leaning Maoist party members.

Five yearly congress overdue

Xinhua said the 18th Party Congress would start in Beijing on November 8, a date later than initially expected. The congress is held every five years.

Nottingham University associate professor Lai Hongyi told Reuters that the late timing was due to continued discussions over the fate of Bo.

 "From their point of view, the top leaders probably would be interested in finishing Bo's case and verdict before the party congress, so it will not become an issue for people to talk about and divert peoples' attention from the party congress. Objectively, that would be the rationale of the party," said Lai.

At the congress, President Hu Jintao is expected to step down as head of the ruling party, making way for his expected successor, Vice President Xi Jinping.

ipj/rg (AFP, Reuters, AP)